We’re a day away from the official announcement of the first phone running Google’s Android mobile platform, T-Mobile’s HTC-built G1. While the phone won’t be out until next month (October 17 remains the date we’re hearing), the device is out there in the wild right now in the hands of select Google and likely T-Mobile employees. In fact, we’ve just received a tip that not only did a G1 make an appearance at a bar in the San Francisco Bay Area over the weekend, but it had a special surprise: An Amazon music and video store application running on it.

Yes, it looks like Amazon will have an app for Android that will complete head-on with the iTunes app on Apple’s popular iPhone device.

Such an app makes perfect sense. One of the key selling points of the iPhone remains the fact that it is also a great iPod music player. The fact that it can connect and download music directly from the iTunes store on the device, is great for getting music on the go. One thing you cannot yet do through the mobile iTunes store however is buy/rent movies or any other form of video. Our source believes that Amazon’s app will allow for that.

The Amazon music store on Android will almost for sure be a mobile version of its AmazonMP3 online digital music store, which is gaining popularity, but still far behind iTunes. Any video store would seem to be based on Amazon’s just relaunched Video On Demand service. It would seem unlikely though that you’ll be able to stream movies over the service, instead, I would bet you’ll only be able to buy them.

We reached out to Amazon for a comment this story, but they declined.

Separately, we’ve heard that another soon-to-be major player in the online digital music world, MySpace Music, will not have a mobile version of its product ready to go anytime soon. The reasoning is that all the rights behind streaming music to mobile devices have not been resolved, John Faith, the general manager and vice president of MySpace Mobile, recently told us.

MySpace music will be largely a streaming music service when it launches (likely at some point this month). Interestingly enough, Amazon will be handling the transactions for people who wish to buy tracks through MySpace Music.

Look to hear more about Amazon’s plans for Android in the coming weeks, if not at the event tomorrow itself.